Cable cutter utilizing a hollow charge explosive



Jan. 12, 1960 D. A. MCBRIDE 2,920,532

CABLE CUTTER UTILIZING A HOLLOW CHARGE EXPLOSIVE Filed May 24, 195'! 2 Sheets-Sheet 1 INVENTOR. D. A. MCBRIDE BY imaflgw ATTORN Y5,

Jan. 12, 1960 D. A. M BRIDE 2,920,532

CABLE CUTTER UTILIZING A HOLLOW CHARGE EXPLOSIVE Filed May 24, 1957 2 Sheets-Sheet 2 FIG.2. FIGB.

23 INVENTOR. D. A. McBRlDE BY ML Wa ATTORNEQS CABLE CUTTER UTILIZING A HOLLOW CHARGE EXPLOSIVE Daniel A. McBride, Silver Spring, Md., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Application May 24, 1957, Serial No. 661,551

3 Claims. (Cl. 89-1) This invention relates to cable cutters and more particularly to an explosively actuated cable cutter for severing a cable while the cable is submerged within a body of water in response to the explosion of a shaped charge disposed within the cutter.

In devices of this character heretofore devised it has been the usual practice to provide a hollow sealed con tainer in abutting relation with the exposed face of the shaped charge to provide a watertight air chamber between the charge and the cable to be severed. This air chamber was required by reason-of the fact that the force of the explosion of the charge was greatly diminished in effect when employed under water unless an air space was provided adjacent the exposed face of the charge. While a sealed air chamber fittingly engaging the exposed face of the shaped charge has in general been found satisfactory to provide an air cushionsuflicient to preventdamping of the shaped charge effect as the charge is detonated, such an arrangement possesses the disadvantage of a substantial increase in the cost of the device and a further disadvantage that the particles of material of which the chamber is composed are disintegrated and interfere to some extent with the effective force of the explosion.

The present invention possesses all of the advantages of this prior art device and none of the foregoing disadvantages. This result is achieved by employing a mass of plastic material such as polystyrene foam or the like between the charge liner and the cable to be cut as will more clearly appear as the description proceeds.

One of the objects of the present invention is the provision of a new and improved cable cutter for use under water.

Another object is to provide new and improved means for excluding water from the outer surface of a shaped charge sufficiently to prevent damping thereof when the charge is fired within the water; a

A still further object is the provision of a cable cutting device for use under water and acuated by the explosion of a shaped charge carried therein having new and improved means for preventing damping the explosive effect of the charge by'the water as the charge is fired at a distance.

Still other objects, advantages and improvements will be apparent from the following description taken in con nection with the accompanying drawings of which:

Fig. 1 is a plan view partially broken away of a cable cutter according to a preferred form of the invention;

Fig. 2 is a side view partially broken away of the device of Fig. 1;

Fig. 3 is another side view of the device of Fig. 1; and

Figs. 4 and 5 are end views of the device.

Referring now to the drawings for a more complete understanding of the invention on which like numerals of reference are employed to designate like or similar parts throughout the several views, and more particularly to Fig. 1 thereof there is shown thereon a cable cutter indicated generally by the numeral and comprising Patented Jan. 12, 1960 a container 11 of generally rectangular configuration adapted to receive and retain an explosive charge 12 therein of the type known in the art as'a shaped charge. A V-shaped liner 13 having two fiat surfaces intersecting to form a V is provided within the container 11, Fig. 2, thereby separating the container into two sections, one section defining a cavity for receiving the shaped charge 12 of generally square cross-sectional configuration which may be a plastic explosive or any other suitable shaped charge explosive while the other section defines a cavity for receiving a filler block 14 composed of suitable filling material such, for example, as ablock of polystyrene foam, thereby to eliminate any damping of the explosive force of the shaped charge due to the fact that water might enter the container and thereby interfere with the explosive effect. The filler block disclosed herein effectively seals the liner and the end of the charge in contact therewith to effect a watertight air chamber thereagainst without employing a hermetically sealed metallic container for this purpose as employed heretofore. container 11 a support 15 having a pair of tracks 16 formed in an end portion thereon, each of the tracks comprising a straight portion 17 substantially parallel to the longitudinal axis of the cutter and a curved portion 18 extending outwardly therefrom.

A clamp member 19 is provided with a pair of bearing pins 21sildably disposed within the track 16 whereby the clamp member is movable from a closed position as shown on Fig. 1 in solid outline to a moved position shown in dashed outline. The clamp member 19 is provided with a V-shaped clamping surface 22 for engagement with a cable to be cut and for clamping the cable to a complementary V-shaped .end surface 23 of the container 11. Pivotally secured to the other end of support 15 as at 24 is a complementary support 25to which is secured a cover 26 composed of material suitable for the purpose such, for example, as wood and adapted to be moved from a position engaging in the end of container 11 to an open position by pivotal movement about the pivot 24. One end of the cover 26 is provided with a pair of clips 27, Fig. 3, for engagement with a pair of notched portions 28'formed within a spring element 29 of generally fiat cross sectional configuration. The'other end of the spring is wrapped about one of the bearing pins 21 as best shown on Fig. 3. The spring 29 is preformed in such manner that the clamp member 19 is normally maintained thereby in the position shown on Fig. l in a yieldable manner such that the clamp member 19 may be moved' at will to an open position shown in dashed outline and thereafter returned to an intermediate position in clamping relation with the cable to be cut by spring 29.

The cover 26 is provided with a pair of spring pressed detents 31, Fig. 2, for engagement with clips 32 at apertures 33 respectively provided therein. The clips are secured to container 11 in any suitable manner whereby the cover is locked in a closed position until the detents have been depressed. The cover 26 is also provided with a bore 34 extending axially therethrough adapted to receive an electroresponsive detonator 35 therein, the leads of which are designated by the numeral 36. The cover is also provided with a threaded bore 37 for receiving a nut 38 threaded therein by means of which the detonator 35 is secured within the cover 26. The nut 38 is preferably slotted at 39 to permit introducing leads 36 within a bore 41 formed within the nut without the necessity of disconnecting the leads from the detonator. The leads 36, hereinafter referred to as fin'ng leads, are connected selectively to a source of electrical energy, the connection including a firing switch (not shown) operable at will.

There is secured exteriorly to one side of within the water, comprising a casing having a V-shaped liner disposed transverselytherein, said liner being con figured by two flat surfaces intersecting to form a V, a shaped charge defined by said liner disposed within said casing, means on one end of the casing for firing said charge, means operable at will for quickly clamping a cable to be cut to the other end of said casing for Let it be assumed, by way of example, that the device is to be employed by an underwater demolition crew and that the operator of the device is of the type known as a frog man. When the' frog man locates the cable to be cut which, in the assumed example, may be the cable 42' shown in dashed outline on Fig. ,1, he places the cutter in a position with respect to the cable such that the projecting end 43 of clamp member 19 engages the cable as shown; A pull applied to the body of the cutter withdraws container 11 away from clamp member 19 sufliciently for cable 42 to be moved into engagement with the intersecting V surfaces 22 of the clamp, the clamp member moving somewhat arcuately away from container 11 during this operation by reason of the curved portion 18 of tracks 16 being engaged by 1 pins 21. Upon release of the pull pressure applied to the cutter, clamp member 19 is movedby spring 29 .reversely toward container 11 until the cable 42 is securely clamped thereto by the V-shaped clamping surfaces 22 and 23 of the clamping member and container respectively. Application of a firing impulse to firing leads 36 causes the detonator to operate and fire the shaped charge 12. When this occurs the "cable 42 is severed at a point substantially coincident with the axis of the cutter by the action of the shaped charge, the force of which is applied to the cable most effectively by reason of the provision of filler block 14 of plastic material which excludes water from the space between the surface of the shaped charge and the cable.

Whereas in the foregoing description the clamp member was moved to open position by pressure of the cable thereagainst, it will be understood that'this has been done for the purpose of illustration only as, if desired, the clamp member may be opened by merely pressing spring 29 toward the container 11 and thereafter allowing the clamp'member to close gently and firmly about the cable.

Preferably though not necessarily the cutter 10 is compresent invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An explosively actuated cutter for a cable disposed severance by the explosive force of said charge, resilient elongated means connected at opposite ends thereof to said casing and clamping means respectively for actuating said clamping means selectively to a cable clamping position, and a quantity of filler material possessing the characteristics of foam polystyrene disposed within and filling that portion of said casing intermediate said liner and the cable forexcluding water therebetween.

2. A device of the character disclosed for cutting a mooring cable beneath the water by the explosion of a shaped charge comprising an elongated casing, aVV- shapedliner composed of thin metal disposed trans- 1 of said sections, means carried by said'cover for firing said charge, a clamp member movably carried by said casing for quickly clamping a cable to he cut across the other end of said casing defining the second section,

and means including a fiat spring pivotally'secured to said clamp member and operable at will for holding the clamp'member in a clamping position thereby to yieldably maintain the cable against said other end of the casing. I v

3. A device for cutting atcable beneath the water by the explosion of a shaped charge comprising a casing having apshaped charge therein, a V-shaped, liner disposed transversely-within said casing and defining said charge, a polystyrene filler disposed within said vcasing and abutting said liner, movable jaw means carried by said casing at one endthereof for securely clamping a cable to be cut in abutting relation with said filler at a predetermined distance from said charge, a cover pivotally secured 'to the other end of said casing, means for releasably locking the cover to said casing, resilient manipulative means secured at one end thereof tosaid cover and at the'other end to said jaw for actuating saidjaw to a cable clamping position, and a detonator carried by said'cover for igniting said charge.

' References Cited in the file of this patent UNITED STATES PATENTS Great Britain June 20, 1956 

